Coated paper



B. C. MILLER COATED PAPER May 10, 1938.

Filed Dec. 17, 1936 FIG 1.

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ROLL

/Y/P R04 L IVE/1 TED RAD/41V 7' #54 THE FEED ROLL RAD/ANT #6 4 TElV/PROLL HEIWZ'D W00 T/il/YG ROLL #671 7549 OIL FIG. 2.

COOL ED MAW-0P WA;

lY/P 1901.1 #674759 vicar/0M6 ROLLS #64769 RAF/ANT #671 526 0/L JACAFTINVENTOR FEED REAL ATTORN EYS Patented May 10, 193

coa'mn rare:

Bert 0. Miller, Montclatr, n. 1., aocignor to am 0. Miller, Inc., NewYork). Y a corporation of New York Application December 17, 1936, SerialNo. 116,218

.rcmm;

This invention is directed to a novel coated web like material such aspaper, cloth and other porous sheets, the method for'coating such sheetsincluding compositions suitable for this process and also an apparatusthat may be conveniently used.

One of the principal characteristics of this process is the applicationto a fibrous base such as paper, cloth and the like, that may normallybe quite porous, of a highly polished, hard, flexible, glossy, tough,adherent coating of any desired color and any thickness varying withinrather wide limits, without any substantial impregnation oi the fibrousbase to produce a waterproof, moistureproof, sheet with advantageouscommercial properties.

Thin transparent glossy films have heretofore been applied to sheet-likefoundations as for example, transparent sheets-of regenerated cellulose,cellulose esters, paper, cloth-and the like, by dissolving film formingsolids, classified as natural and artificial resins, cellulose esters,waxes, etc., in volatile solvents to form lacquers. Such lacquers werethen applied to the sheet-like materials to form a coating thereon. Manyof the products so produced had substantial com mercial value but therewere a number of disadvantages both in the processes of coating the baseand also in the coated articles produced that limited the usefulness ofsuch processes and articles.

For example, in the commercial process for lacquering paper there areserious related limits. tions as to time involved and thickness ofcoating. When a solution of a coating composition is ap plied to thebase it is necessary to remove the solvent before the coatingcomposition is dry and can be put in contact with any other surfacewithout adherence. In applying a lacquer coating to paper, .for example,it is necessary to dry the coated paper and in normal apparatusemploying heating ovens or towers it requires a great deal of spacethrough which the paper must be passed to heat it for a long enough timeto remove the solvent. During this drying period it is necessary thatcontact of the coated surface with any other surface be avoided and toobtain this, when the sheet is coated on both sides, complicatedapparatus to air float the paper has been necessary. There has also beena very great economic loss in the evapolation of the solvent which isnormally not recovered. Since the paper cannot be exposed to very hightemperatures the time involved in drying the coating requires relativelylarge ovens or towers that take up a great deal oi space within theplant. This results in very definitely limiting the rate of speed atwhich a iacquering' process can be conducted.

As a matter of fact, in ordinarycommercial lacquerlng a speed of about125 feet per minute 5 is rardinarily'the maximumspeed that can be useLacquerlng processes are also very definitely limited in thethiclmess ofcoating 'which may be applied. If it is attempted to apply a relatively10 thick coating in a single operation, the time required for drying isvery greatly increased and the diilicultles inherent therein aremultiplied. When attempting to secure a relatively thick coating in alacquering process, it is generally 5 desirable to apply aver-a1 thincoatings because this can be more conveniently done than to apply asingle thick coating. To obtain a four to seven pound coating per reamrequires at least two and preferably three separate applications oflacquer. Obviously passing the base through a machine a plurality oftimes increases the cost of production and reduces the output.

Another disadvantage inherent in lacquering processes is the danger ofexplosion or fire from the evaporation ofthe solvent. The lacquer may beapplied in a number of ways as for example, by spraying, by applying torolls which are brought into contact with the paper or by dipping theroll into an open bath of the liquid and transferring the lacquer fromthe roll to the paper. In all; of these methods there is a substantialevaporation of the solvent at the point ofapplication and likewise afterthe coating has been applied whenthe solvent is removed. -In thesecases, a volatile solvent which is generally inflammable, permeates theatmosphere in the neighborhood of the apparatus and creates asubstantial fire hazard. This is particularly important in large papermaking and paper products tfiltories where the tire hazard is great atany t e. I

There have been, of course, many improvements -made in the lacqueringprocesses, as for example, more volatile solvents have been employedwhich thereby reduce the drying time required. However; most of thesolvents as they become more highly volatile are also more expensive andthe cost of the process is thereby increased.

' The product produced by lacquering has certaln characteristics thatcan be readily distinguished. For example, in a lacquer paper there issubstantial impregnation of the paper itself by the solids contained inthe lacquer. The volatile solvents being able to wet or penetratebetween the fibers of the base, carry a substantial amount of thecoating into the interstices of the base thereby taking it away from thesurface, and, where the primary object is coating the surface,increasing the cost thereof. In addition. all lacquers must have thesolvent removed and the solvent in evaporating through this film tendsto make ,it somewhat cloudy and the transparency or alternatively thegloss of the coating is thereby reduced since an absolutely smoothsurface is normally not obtained. This is also due to the fact that thecoating is to a great extent influenced by the irregularities in thesurface of the base being coated.

Lacquer papers are desirable for packaging but are subject to a verydefinite limitation in that they donot readily lend themselves tothermoplastic adherence. Some lacquered papers can be heated and a sealobtained thereby but the seal is generally quite weak.

It is an object of this invention to produce a new type of coatedfibrous-base.

Another object is the provision of a porous fiexible sheet at least oneside of which has a flexible waterproof synthetic resin; coating,comprising a plasticized polybasic acid-.-,-polyhydric alcohol resinsolid at normal temperatures, with a high gloss, hard smooth finishindependent of minor variations in the surfaceq of the sheet strictlyconfined to the surface of the porous flexible sheet.

A further object resides in providing a process for coating flexible,fibrous bases without the use of solvents to distribute the coatingmaterials.

To this end it is an object to provide a process for producing a highlypolished thin flexible surface film' firmly attached to a porousflexible base free from impregnation by the material composing the filmwhich comprises providing a melt of a plasticized synthetic resin solidat normal temperatures, applying the resin to a surface of the flexiblebase at a temperature of not substantially exceeding about three hundreddegrees Fahrenheit to form a thin flexible surface film of substantiallythe same composition as the melt which solidifies solely by cooling.

These and other related objects which will hereinafter be set forth orapparent from the sequent description in which is set forth certainpreferred illustrative embodiments of my invention are all embracedwithin this invention.

This invention seeks to overcome the disadvantages of the prior art inthe production of coated fibrous bases as for example, paper, cloth andthe like but is illustrated particularlyas applied to paper. This isaccomplished by the provision ofa new method for coating fibrous bases.of the type described and includes broadly the and through the base.

ever, that the ordinary materials used as the film application of amelted body of resinous material that solidifies solely by cooling,thereby dispensing with the necessity of dissolving a coating materialin a solvent, and then disposing of the solvent by evaporation from thesurface of the applied film It has been found, howforming ingredient inlacquers cannot, as a general rule, be employed in the process formingthe subject matter of this invention to obtain the new productsdescribed herein since the materials selected must comply with certainspecific requirements that I have discovered are necessary to obtain apracticable process for coating porous bases without the use of avolatile solvent.

Lacquers comprise various ingredients including cellulose esters andtheir plasticizers, various types of resins, esters, ester gums, waxes,etc. Considering for example, one of the usual constituents of alacquer, a cellulose ester, such materials cannot be used in anysubstantial quantity in this process because they either have too highmelting points or what is more important too high a liquefaction pointto be applied to fibrous bases successfully, or if they can be madesufliciently fluid at a lower temperature they do not form a film on thepaper which is non-tacky or hard to the touch at normal temperatures buton the contrary, when rolled in a roll or when sheets are piled on eachother they tend to stick together and form a solid mass instead of aplurality of individual coated sheets. This situation also occurs withmany of the natural resins commonly employed in lacquers. Othermaterials, as for example, some of the synthetic and natural resins aresolid at normal temperatures and can be liquefied at relatively lowtemperatures but cannot be used in commercial practice because they havethe property of cold flow". That is, they tend to flow slowly butperceptibly upon extended exposure to ordinary temperatures. Many arelikely to polymerize when kept at the temperature .required for a fluidbath so that instead of forming a. uniform film they graduallypolymerize to a viscous, plastic or solid mass in the bath or on therolls that makes the machine, by means of -which they may be applied,totally inoperative. It is therefore essential that the coating materialselected should be capable of being heated to the temperature at whichit is liquid and not polymerize or otherwise solidify at thattemperature over a period of a. few hours.

Another important consideration is the natural thermal properties of thematerial selected. It is important that when applied to the base as athin film that the material must be hard and flexible up to atemperature of approximately 120 Fahrenheit. Higher melting pointmaterials when coupled with adherence to the base and flexibility atnormal temperatures are suitable. It is likewise essential that thematerial be one which will melt to form a thin-fluid at a temperaturebelow that at which the base is damaged or, in the case of paper notsubstantially exceeding about 400 Fahrenheit and preferably below about300 Fahrenheit. a viscosity such that a 1; inch steel ball will fallthrough ten inches in less than about seconds and in commercial practiceless than thirty seconds has been found most advantageous. The mostdesirable materials are those with a sharp drop in viscosity over asmall temperature range, preferably over a temperature gradient of 30 to50 Fahrenheit in order that the material when applied to the basewillsolidify upon a small change in temperature to provide a surface that ispermanent and which upon a. slight additional cooling will be non-tackyand therefore can berewound or stacked in sheets without the hereto.-fore inherent danger of forming a solid mass.

By thin fluid is meant A very large number of natural and syntheticresins have been tested in this process and as -tc their physicalproperties in an effort-to ascertain those which met the qualificationsoutlined, and.

could be successfully used.

As a result of these tests, it was found that there were relatively fewresins that could be used. Some were satisfactory as far as theirthermal properties were concerned but tended to polymerize or hadobjectionable odor or color in thin films. thers which were not subjectto the disadvantages of polymerization were either a1 mooo too tacky atnormal temperatures or had too high melting points or had to be heatedto role. tively high temperatures before they were sulficiently fluidfor proper application to the base. In no instance could a single typeof resin by itself be successfully employed. By this it is not meantthat the resin as originally prepared could not ,be employed but simplythat the ,esteriflcation or condensation product of most resin reactionswhen carried out under the conditions which produced a single resin didnot produce resins with the proper properties. However, it is possiblein the preparation of the resin to include a, modifying ingredient thatmight be an excess of one of the reactants, the addition of one or morereactants or an added modifying agent which will control the propertiesin a manner to make the productproduced useful in this process. In somecases the incorporation of a diluent type of plasticizer as for example,non-drying oil has been found successful. One of the most convenientways of modifying a resin is that involving the incorporation of a verysmall amount of wax as for example, a hydrocarbon wax'in the resin meltbefore it is applied to the paper. From about three to five percent isusually sufficient.

. The wax has a number'of desirable functions ineluding that ofplasticizing the resin to produce a flexible non-tacky moistureprooffilm when applied io the base. In addition it is quite important as alubricant for the rolls which may be employed to apply the resin to thesurface of the base. Furthermore, a wax smooths the surface of the film.It likewise has some influence in controlling the temperature at whichthe resin is fluid. Other true plasticizers including dibutyl phthalate,tricresyl phosphate, diamyl phthalate, hydrogenated esterified rosin,and other chemcally inert high boiling, colorless and odorless liquidsmay be used either alone or with was.

In practice it has been found convenient to form a melt of the selectedcoating material which is maintained at a temperature sufficient to makeit a relatively thin fluid. This should be at not substantiallyexceeding 300 Fahrenheit and preferably at a somewhat lower temperaturebut at which the liquid is quite fluid. A heated rotating roll at atemperature which gives the melt a viscosity such that a it; inch steelball will fall through ten inches in less than 20 secends is dipped intothe melt, picks up the coating material and forms a thin film on theroll; This is carried to the point of contact with thepaper which wouldbe between the first rolland a secand heated roll acting together as niprolls. These rolls should be capable of minute exact clearanceadjustment, The paper is fed between the rolls from a suitable source ofsupply and may or may not be preheated When the paper leaves the niprolls and the coating has been applied to one or both sides ifdesirediit then passes to a third roll ro ating in a direction oppositeto that in which the paper is, progressing. This roll is heated and actsto smooth the surface of the film. The smoothing roll and the; nip rollsare conveniently heated as for-example, by hot oil or super-heated steamto a temperature about that of the bath; After the film on the paper hasbeen smoothed by the smoothing roll it will have a high gloss but willshow imperfections of this roll even if it is highly polished andchromium plated. It has been, found" that improved results are obtainedif the paper is then passed by but not directly in contact with a heatedplate at a relatively. high temperature. The

. paper in contact with a chill roll to assist in setting the coating.For a relatively thin paper a stock and a thin coating the chill roll isgenerally not necessary. When a thicker paper stock is employed or if athick, coating has been applied a chill roll maintained at, temperaturesbelow freezing is desirable. Speeds up to 500 linear feet per minute maybe maintained.-

The product produced by this process has a number of advantageousfeatures over those heretofore known and differsin many substantialrespects from the lacquered papers of the prior art. Since the coatinghas been applied as a melt instead of with a solvent, the coated paper,whether rag, kraft, glassine, embossed or other types, has the coatingconfined substantially to the surface, there being little or noimpregnation into the body of the paper, because the coating materialwhen it touches the exposed fibres of the paper rapidly solidifiesthereon and forms a. tight bond therewith but does not go into theinterstices of the paper. The coating has a very high gloss and issubstantially, more polished than is true of the solvent appliedcoatings. This is due to a number of factors including thatof the lowwax content which does not leave the greasy feel inherent in acoatlngwith a high wax content as iscustomary in many lacquers.-.'I'here is likewise a continuity of film produced by the fiuxing ofthe melt which is not disturbed by the removal of a solvent vehicle. Thecoating is also.

extremely useful to form a strong thermoplastic seal. When the paper isemployed as a wrapper which is to be sealed and the desired port-ion isheated for a very short time and held under pressure, the heated portionfirmly adheres to that with which it is in contact and forms a verytight seal that cannot ordinarily be broken without tearing the paperitself.

The character of the coating can be controlled in many respects sincethe melt takes pigment better than do lacquers and the pigment may bedispersed'uniformly throughout the film. Colored papers may be employedas bases if desired and if they have printing on them or any other typesof coating that would be soluble in the solotherwise known as alkydresins, have proven to be the most successful since many of these haveproperties which fulfill the requirements above set forth. For example,a phthalic-anhydrideglycerol type of resin with a small amount of aplasticizer, three to five percent of wax, has been successfullyemployed in this process to give a commercially acceptable product.

As stated above shellac which has some of the properties required foruse in this process cannot be employed alone. However, it has been foundthat up tobut not exceeding about forty percent and preferably abouttwenty percent can be incorporated in an alkyd resin base to form asuccessful coating. The shellac when incorporated with the resinproduces a film with a very hard surface at normal temperature yet formsa gooding packages. The addition of a vinyl resin produces a tougher andfirmer film.

Toluol sulfon-amide resins or generically, the condensation products offormaldehyde with aromatic sulfon-amides can be substituted for thealkyd resin. These resins while water white and therefore form a clearfilm are subject to cold flow and require a hardening agent such as aphenol formaldehyde resin.

Another composition which has been successfully employed comprised about40% of phthalicanhydride-glyceride resin, 30% of chlorinated diphenyl.15% of a'vinyl resin and 15% of a phthalate plasticizer which produced ahard flexible coating with a very high gloss or polish. Thephthalic-anhydride-glyceride resin, or alkyd resin should be present inamounts sufilcient to give the coat the desired high polish and greaserepellent character. If .the particular alkyd resin employed also hasthe desired properties of adhesiveness and flexibility it may comprisesubstantially the entire coating composition especially where modifiedwith a small amount of a true plasticizer or'a diluent type ofplasticizer and preferably with the inclusion of a smallamount of waxwhich assists in producing a moisture proof film.

The vinyl resin may be one produced from vinyl esters of acetic acid ormonochloracetic acid, vinyl acetate, vinyl chloride, etc. Particularlysuccessful in this combination is a polymerized mixture of vinyl acetateand vinyl chloride which with the alkyd resin increases the elasticity,flexibility and hardness to the touch of the coating. It is usuallyemployed in not exceeding about 25% of the entire coating composition.

Where an adhesive is either necessary or desirable it is convenientlyused in amounts between about ten to thirty percent. The adhesiveassists in producing a firm bond between the coat and the foundation andprevents the film from checking or flaking off.

In the compositions described above it may be desirable to add variousfillers, as for example, a phenol formaldehyde resin may be added in portions up to about or 30 percent and in some cases as high as 50 percent.Likewise white or colored pigments of various types, as for example,titanium dioxide or cadmium selenide, etc. may be incorporated to colorthe film. In addition where pastel shades are sought it has been founddesirable in some instances to include a dye. The dye is preferably usedin connection with a pigment since the heating treatment,

when the melt is formed, tends to decompose dyes and they lose theircolor but the presence of a pigment reduces this tendency. It is alsopossible to use this process with colored bases and a transparentcoating in which case the color of the base is not only retained but isgiven a better appearance by the transparent coating on it. Furthermore,when a colored ink or a black ink is applied to the coating the inklooks more brilliant than when applied to coatings from which a solventhas been evaporated.

The accompanying drawing shows diagrammatically an apparatus that may beused to carry out the process of coating fibrous bases such as paper,.orcloth according to the teachings of this invention.

Figure 1 is directed to a simple apparatus that is conveniently usedwhen only one side of the web is to be coated; while Figure 2 shows anapparatus that may be used when both sides of the web are to have acoating applied.

Obviously the apparatus of Fig. 2 may be used for coating only one sideif desired.

As illustrated in Fig. l the web is drawn from a feed roll over suitableguiding rolls to the upper nip roll which is preferably heated to thetemperature of the melt. If the paper is carried around this roll for ashort distance as is illustrated in Fig. 1 it is preheated but in thiscase on the side opposite that to which the coating is to be applied. Aspaper is a non-conductor, the surface to be coated is only slightlyheated and the paper is not as a whole heated to a very hightemperature. .A radiant heater is adjusted close to but not in contactwith the surface of the paper which is to be coated at a point justbefore the coating is applied. The paper then passes between the top niproll and bottomnip roll. The bottom nip roll dips into a melt of thecoating material which is kept at the proper temperature to insuresufiicient fluidity by a heater beneath it. The melt may be at anydesired temperature depending upon the character of the material formingthe melt. It should not be necessary ordinarily to heat the melt to atemperature higher than about 300 Fahrenheit and lower temperatures arepreferable subject however to having sufilcient fluidity. .The lower niproll dipping into the bath picks up a film of the coating material andcarries it to the point where it is applied to the paper, the amountdepending upon the adjustment of the distance between the two rolls. Thepaper, now coated on its lower face, leaves the nip rolls and the coatedsurface is passed in contact with a smoothing roll, rotating in adirection opposite to that in which the paper is travelling. Thesmoothing roll is likewise heated to a temperature substantially equalto that of the bath as for example, by passing hot oilor super-heatedsteam through it. The smoothing roll is provided with a highlypolishedsurface to avoid transferring imperfections to the film. The paper thencontinues and is passed over a radiant heater which is kept at arelatively high temperature and on the same side as the film but out ofcontact therewith. This causes a slight fusion of the'extreme outersurface of the film and produces a uniformly smooth surface. The paperthen continues to a wind-up roll or if desired over a chill roll. Sincethe coating material solidifies upon cooling through a small temperaturedifferential and will cool rapidly in passing through the air the filmsets immediately and is substantially hard by the time it reaches thechill roll where it may be further hardened by the cooling impartedthrough contact with the chill roll which should be capable of sub-zerocooling by refrigeration when necessary. After this the web is wound ona wind-up roll or may be cut into sheets or strips as is desired. Whenemploying the compositions described in this application, the coatedpaper upon normal cooling or upon chilling is non-tacky andwill notadhere to an adjacent sheet.

The apparatus of Figure 2 is in many respects similar to Figure 1 exceptthat the web does not contact with either of the adjustable nip rollsexcept where they are both in contact with the paper accordingly, thepaper maybe preheated as by the radiant heaters before it goes betweenthe nip rollers. While the coating composition is applied to the lowernip roll in the same manner as is illustrated in Figure 1, the upperroll is sup plied by providing a melt kept at the proper temperature bya heater beneath the vessel or an oil jacket. The resin or other coatingcomposition may be melted in another vessel and supplied through pipes.Melted coating composition is fed to a doctor blade through a valvedpipe in which the valve controls the amount of flow and thereby theamount of material between the doctor blade and the nip roll. Thethickness 'of the film h on the nip roll is controlled by the spacing ofthe doctor blade fromthe roll. Each of the nip rolls thereby has a filmon its surface which is brought into contact with and then transferredto both sides of the web. After leaving the nip rolls the smoothingrolls on either side rotating in a direction opposite to the directionof the web smooth the surfaces and radiant heaters are provided on bothsides of the web to fuse the extreme outer surfaces. If desired, insteadof applying the film of coating material to the lower nip roll from amelted bath, as illustrated in the two figures, the lower nip roll'maybe supplied with coating material in a manner similar to that shown forapplying it to the upper nip roll in Figure 2.

The process may be carried out at any speed the base stock will permit.In commercial practice speeds ranging from as low as about feet perminute to as have been successfully run.

The thickness of the coating can be readily controlled in a number ofways. As stated above, it is convenient to have the nip rolls accuratelyadjustable withinrather wide limits in order that the apparatus mayaccommodate any desired weight of paper and thickness of coating. Withthis process coatings varying from about two pounds per ream up to ashigh as ten pounds per ream can easily be applied in a singleapplication. The thickness of coating can likewise be controlled within.certain limits by the viscosity of the melt which is subject to thetemperature to which it is heated or to which the rolls are heated whenthe melt is applied as well as by the speed the web is passed throughthe rolls.

' It will thus be seen that I have provided a process for coating porouswebs without the use of any volatile solvent by a process which has anumber of important advantages, i. e., high speed of operation since noheating of the coated stock or evaporating steps are necessary, compactand economical mechanical equipment, economy of operation, eliminationof fire rds, improved characteristics of the finlshed'products in thatthey can be made with varied degrees of gloss any desired color bypigmentation, water resistant, high moisture proofness, grease prooinessand then'noplasticity.

high as 500 feetper minute General characteristics of finished paperflat by varying the character of the smoothing roll and omitting theradiant heaters, or any intermediate finish desired. As no dissolvingagents are employed, any finish or lustre desired is easily obtained andpermanently kept. The surface is smooth and uniform, not greasy, hard tothe touch and repellent to dust and dirt. It is free from cookies causedby solvents or moisture. The coating may be water white, transparent orany desired color or degree of opaqueness.

Resistant qualitiea-As the resinous coating itself is not readilysoluble in common solvents, the resistant characteristics are very highto grease, oils, fats, etc. Moist'ure-proofness is inherent and perfectcontinuity of the film is insured by the hot-melt method of application.Tests on moisture-proofness have shown this product to be several timesmore moisture-proof than moisture-proof cellophane", which is normallyregarded as zero.

Thermoplastic qua1ities.-In packaging. or in any use where papers are tobe sealed, the thermoplastic quality is very important. My base materialis a true plastic. At certain temperature ranges it is soft. When it isused as a thermoplastic for sealing purposes, once it is sealed, it isan extremely strong and secure binder. It

cannot be readily pulled apart and rescaled.

General characteristics-This material is fast against light,non-poisonous, non-contaminating and odorless. As no solvents areemployed in its application, there is no solvent odor. The material isalso non-hygroscopic and the finished sheet coated with it has none ofthe disadvantages connected with water-applied coatings,

such as curling, blistering, and the development of corrosion.

This application is a. continuation-in-part of my copending applicationSerial'No. 716,504, filed March 20, 1934:, for Art of coating andlaminating fabrics.

Having thus described my invention with examples of certain preferredembodiments what I claim is:

1. The process of providing a high gloss thin surface film firmlyadhering to a porous flexible base free from impregnation by thematerialcomposing the film which includes melting a synthetic resinouscomposition comprising the plasticized reaction products formed by theesterification of a polybasic acid by a polyhydric alcohol which isflexible, hard up to about 120 F. and non-blocking at normaltemperatures, applying the molten resin to a heated element to form afilm thereon, transferring the said film to a surface of'the flexiblebase at a temperaturebelow that at which the fluidity of the resin ishigh enough to cause substantial impregnation of said base, and quicklysolidifying the resinous film substantially entirely by cooling beforethe film .has substantially impregnated said foundation about 120 F.,flexible, non-blocking at normal temperatures substantially confined tothe surface of the sheet and substantially identical with the productproduced by the process of claim 1.

3. The process for producing a highly polished thin flexible surfacefilm firmly attached to a porous flexible base free from impregnation bythe material composing the film which comprises melting a. resinousmaterial which softens at above about 120 F., is fluid below about 300F. and will not solidify by polymerization in the melt and, while theresinous material is at a temperature not substantially exceeding about300 F. but at which it is of a viscosity permitting a inch steel ball tofall through ten inches in less than about one hundred seconds, forminga fluid film of the molten resinous material transferring said film to asurface of the base to form a thin'flexible surface film ofsubstantially-the same composition as the molten resinous material whichsolidifies solely by cooling, setting the film before substantialpenetration and heating the exposed surface of the film to smooth it.

4. The process for producing highly polished thin flexible surface filmsfirmly attached to a porous flexible base free from impregnation bythematerial composing the films which comprises melting a resinous materialwhich softens at above about 120 F. is fluid below about 300 F. and willnot solidify by polymerization in the melt and, while the resinousmaterial is at a temperature not substantially exceeding about 300 F.but at which it is of a viscosity permitting a inch steel ballto fallthrough ten inches in less than about one hundred seconds, dipping aroller,

into a melt of theresinous material to form a film thereon, applying themolten resinous material to the surface of a second roller mounted abovebut in contact with the first roller to form a second film thereon,passing the base between the two rollers to transfer the molten filmsthereto to form thin flexible surface films of substantially the samecomposition as the molten resinous material which solidify solely bycooling,

setting the films before substantial penetration and heating at leastthe exposed surface of the films to smooth them.

5.1m article of manufacture comprising the combination with a porousflexible base, of a high gloss thin film of a fused synthetic resinousmaterial firmly adhering to at least one side thereof, which. is solidup to about 120 F., flexible, nonblocking at normal temperaturessubstantially confined to the surface of the sheet and substantiallyidentical with the product produced by the process of claim 3.

6. The process for producing a highly polished thin flexible surfacefilm firmly attached to a porous flexible base free from impregnation bythe material composing the film which comprises melting a resinousmaterial which softens at above about 120 F., is fluid below about 300F. and will not solidify by polymerization in the melt including up toabout 5% of wax and, while the resinous material is at a temperature notsubstantially exceeding about 300 F. but at which it is of a viscositypermitting a inch steel ball to fall through ten inches in less thanabout one hundred seconds, forming a fluid film of the molten resinousmaterial, transferring said film to a surface of the base to form a thinflexible surface film of substantially the same composition as themolten resinous material which solidifies solely by cooling, setting thefilm before substan-

